Contaminated surfaces are not thought to be significant in the spread of coronavirus, according to US health officials, as scientists said that an anti-malarial drug promoted by President Trump had no benefit and increased the risk of death.

Close contact with an infected person is the primary way of catching the virus, according to the latest advice from the Centers for Disease Control and Prevention (CDC), the main US public health body.

“Covid-19 spreads mainly through close contact from person to person,” it said after a review downgraded the role of contaminated surfaces.

A separate CDC report analysed a so-called superspreader incident at a choir in Washington State when 52 people fell ill after singing with one symptomatic member at a two-and-a-half-hour indoor practice on